Modern day vehicles include a variety of electronic systems for the convenience of a vehicle owner. Vehicle door lock systems are one example. A vehicle owner no longer needs to insert a physical key into a door lock on the outside of a vehicle to unlock a door for purpose of entering the vehicle. Capacitive detection systems allow for a control unit on the vehicle to communicate with an authentication device carried by the vehicle owner upon detecting an individual's hand on or near a door handle. If the control unit obtains appropriate authentication information, the door is automatically unlocked and the individual only needs to manipulate the door handle once unlocked.
Most such door systems operate in one of two general ways. Some such systems measure a rate of change in capacitance while others attempt to measure absolute capacitance for purposes of determining when an individual is intending to open a door. One shortcoming associated with systems that rely on a rate of change is that they are subject to false detections when conditions around the vehicle affect the manner in which the hand detection device operates. For example, when the vehicle is exposed to rain, the presence of water can change the capacitance in a manner that the system interprets as an attempt to open a vehicle door. False detections are undesirable because they result in the control unit attempting to communicate with an authentication device. Such communications require electrical power and may tend to drain the vehicle battery.
One drawback associated with systems that rely upon absolute capacitance measurements is that an individual wearing a glove may be frustrated that the door is not unlocked in a timely fashion because the glove is interfering with the systems' ability to detect the individual's hand.
There is a need for improvements in vehicle entry systems that utilize capacitive-based detection techniques to avoid false positive detections for saving energy and to more consistently detect an attempted vehicle entry by an authorized individual.